Plant derived secondary metabolites in cancer therapy: actions, applications, and future prospective of dietaryflavonol (quercetin)

Abstract

Higher plants are prominent sources for several bioactive chemical constituents (secondary metabolites) who include photochemical, flavoring agents, fragrant molecules, and food additives. According to WHO estimates, it has been reported that more than 80% of population in developing countries prefer these natural bioactive active compounds for their primary health requirement. At present, conventional chemotherapy is constrained due to the nonselective toxicity to human organs and their usage is limited now a days. In a recent survey, more than 60% of cancer patients have been preferring adjuvant phototherapy along with chemotherapy. Thus, photochemical are being widely used as anticancer agents to target specific pathological pathways underlying cancer with low toxic profiles and side effects. These photochemical are cost-effective and easily accessible to the public to treat cancer diseases. These bioactive photochemical are meticulously belongs to secondary metabolites such as alkaloids, flavonoids, polyphenols.Among them, the flavonoids are polyphenolic substances, which are found in all parts of the plant such as flowers, fruits, leaves, roots, seeds, and bark. They possess high medicinal properties like being anti-cancer, anti-hypertensive, anti-inflammatory, anti-obesity, anti-malarial, antioxidant agents. Quercetin is major flavones associated with a profound antioxidant and medicinal property to prevent the oxidation of lipids in vitro and in vivo, and also exhibits direct proapoptotic effects on tumor cells. This compound has proven efficacy in targeting several cancer cells of breast, colon, prostate, ovarian, and lung tumor in vitro. The present review focuses on the effect of quercetin in cancer therapy.